From the original definition of the PMC in an article where the term and acronym was first coined:

We define the Professional-Managerial Class as consisting of salaried mental workers who do not own the means of production and whose major function in the social division of labor may be described broadly as the reproduction of capitalist culture and capitalist class relations.

The article would go on to list a hodgepodge of jobs ranging from classic labor aristocrat jobs like engineers to middle management types who don't actually own the means of production (I'm guess this is what you're alluding to in your comment) to "workers concerned with the production of ideology" like teachers, social workers, psychologists, and entertainers. This is why I despise the term PMC. It's a trash term that absolutely no one uses in its original definition, which honestly already kinda sucks. In practice, people use it to mean some kind of labor aristocrat working in a white collar job like a software dev or HR manager even when not every labor aristocrat works a blue color job and not every white collar worker is a labor aristocrat.

Notice the hyphen in "professional-managerial" that people today omit. It's very intentional by the original authors. They don't mean managers who work in a professional settings constituting its own class, but professionals and managers together constituting its own class. So, the PMC (professional-managerial class) is simply PC (professional class) + MC (managerial class). They have a table which lists the numbers of certain sectors of the PMC, the sectors being

• engineers

• manufacturing managers

• social, recreation, and religious workers (other than clergy)

• college faculty

• accountants and auditors

• government officials and administrators

• editors and reporters

It's basically laborers who do intellectual, administrative, and supervisory work. Like, arguably every single white collar worker would count as a PMC, which the article seems to be pushing although I haven't gone through the whole thing.